<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>一元运算符</title>
</head>
<body>
按字面值转，是数字就是数字，不是数字就是 NaN <br>

<script>
var a = 3;
var b = 4;
document.write(a+b + '<br>');
document.write(a-b + '<br>');
document.write(a/b + '<br>');
document.write(a*b + '<br>');
document.write(a%b + '<br>');
</script>
<br>
</body>
</html>